Process of promoting the bloating of earthy materials



I lular product, it has been found that Patented Apr. 18, 1933' UNITED STATES PATENT OFFICE snnauAN. 1;. LEE, or mAmsoN, wrscousm, ASSIGNOR, BY MESNE Assrqmn'rs, 'ro AMERICAN FACE BRICK nnsnAnon coaron 'rron, A CORPORATION or rumors PROCESS OF PROMOTING THE BLOATING OF EAR'I'HY MATERIALS No Drawing;

This invention relates to process of promoting the bloating of earthy material.

In the bloating of argillaceous or similar earthy materials in the production of a celwhile many of the clays in their natural state contain all of the ingredients which adapt them to successful treatment at bloating tempera-- ture, there are clays which cannot be successfully bloated while in the natural state and which require the addition thereto of suitable ingredients which at the bloating temperature will evolve gases and thereby cause an expansion and bloating of the mass with the formation throughout of minute cells or cavities.

Attempts to treat such non-bloating clays have in the past beenmade by the expedient of adding thereto and admixing therewith particles'of solid carbon or other ingredients which were burned out during the firing operation, but such a method of adding ingredients requires a very fine and complete admixture of the gas producing or combustible materials throughout the mass, which greatly increases the cost'of production and at the same time renders it diflicult if not impossible to produce a truly cellular product, such as is claimed applications.

The object of the present invention is to avoid the'difliculties which have heretofore been encountered, and to provide a practical method for the treatmentof non-bloating clays, by adding to the mass a quantity of gas forming ingredients in the liquid rather than in the solid state, 'which permits such fadded ingredients to be thoroughly and completely admixed with the clay or similar earthy material, so that during the firing operation the gas forming ingredients will be present and thoroughly disseminated throughout the mass, so that a substantially uniform cellular structure will be obtained.

In 'carrying out the process 1n conformity With the principles of the present invention,

, liquid which at it has been found desirable not-only to add a carbon carrying liquid but also to add a the bloating temperature will supply oxygen, so that during the bloating in this and co-pending Application med 'm a, mo. Serial No. 465,653.

of themass there will occur a combustive reactlon which results inthe liberation of carbon monoxide and/or carbon dioxide gas,

which ebullition of gas within the interior results in the formation of the cells or cavities requisite togive to the product the cellular structure required.

Although in some circumstances it is possible to secure desirable results by permitting the granular particles of clay or the like to absorb the requisite amount of the gas forming liquids while in the granular state, it is preferred to add such liquids as a tempering medium and to reduce the entire mass to a plastic condition, with the gas forming liquids thoroughly admixed with and incorporated into the plastic mass, which thereafter is extruded or otherwise molded into block form, and as a block is first subjected to a preheating temperature within the confines of a furnace or kiln.

As the block becomes heated, a violent ebullition of steam will shatter the block and again reduce it 'to a granular condition in preparation for the subsequent bloating; the solvents will be driven off, and the solids in minute particles of colloidal size will re main within the granular particles and thus supply the chemicals required for bloating. This method of introducing the gas forming ingredients while in liquid condition permits of a much more uniform and complete distribution than is possible where solids are incorporated and mixed with the clay while in a dry state.

Since it is necessary gas forming ingredients in liquid form, soluble materials must becchosemand I have found that satisfactory results may be obtained by the employment of such material as molasses, which furnishes the carbon required, and ferrous sulphate, FeSO which supplies oxygen, and iron, which being a flux lowers the temperature necessary, to produce bloating.

When the mass is subjected to a bloating temperature, a reaction of the oxygen hearing material, such as FeSO withthe carbon bearing material, such as molasses, oc-

to incorporate the 100 parts of such clay in granular form I add a mixture composed of the following ingredients:

Molasses l to 5 parts.

FeSO. 1 to 2 parts."

These ingredients-are dissolved in a quantity of water sufiicient to reduce the clay to a plastic mass. The liquid mixture is thoroughly incorporated with the clay, which is kneaded in the usual manner until it is re duced to a plastic mass having the liquids thoroughly incorporated and distributed throughout, after which it may be fed from a pug mill and severed in the form of bricks or blocks of convenient size.

The bricks or blocks are thereupon, while still moist, introduced into a preheating kiln and subjected to a preheating temperature, which for certain clays may be in the neighborhood of from 1500 F. to 1800 F., and in all cases should be below the temperature at which the clay or other earthy material begins to soften and become sticky.

When the Wet or moist bloeksor masses are subjected to the preheating temperature, an ebullition of steam will ensue, which causes the blocks or masses to be shattered with almost explosive violence. As a result, the mass is again reduced to a granular state and in condition for the subsequent bloating operation. The mass, after being thus reduced to a granular state, and after being thoroughly preheated, is fed in granular form to a bloating chamber, where it is spread or otherwise manipulated into the desired form for bloating and subjected to a bloating temperature, which in the case of certain clays may be in the neighborhood of 2200 F. for a suitable length of time to permit the mass to become thoroughly and uniformly heated throughout, which results in a chemical reaction of the carbon and oxygen supplying ingredients which liberates the gases 1n 'situ throughout the mass and causes bloating to the desired degree. The presence of these added ingredients also favorably influences the heating of the mass by internally generated heat due to the combustion of the ingredients, so that in most cases bloating can be eifected by the application of less external heat than would be otherwise required.

It will be understood, however, that the temperatures given aremerely by way of example, and that in each case the appropriate temperature will be applied for a'proper length of time to secure bloating to the desired degree and the formation of a cellular product having a structure of the desired density.

After the block has become thoroughly bloated, it is removed from the bloating zone while still in pliable or semi-plastic condition, and subjected to a slightly reduced soaking temperature intermediate the bloating temperature. and the congealing temperature, and is allowed to soak until all internal stresses have been eliminated, after whichit is gradually cooled to room temperature and either utilized as a building unit in its completed form or sawed up into smaller sections as occasion may require.

The utilization of the present process enables non-bloating clays to be satisfactorily treated in the localities where such clays are found, but it is not the intention to limit the invention to the treatment of such clays,

' since other clays which can be bloated in the natural condition may be additionally treated in accordance with the present invention, where it is desired to increase the bloating properties or to reduce the bloating temperature, and in such cases the bloating ingredients will be added in the required amount to supply any natural deficiency in the presence of gas forming ingredients or in an amount necessary to hasten the bloating period or reduce the temperature thereof to the desired limits.

I claim:

1. The process of promoting bloating which consists in adding to a mass of earthy material a liquid containing molasses and FeSO, in solution and incorporating the same throughout the mass of earthy material and in sub ecting the mass to temperatures adequate to first evaporate the solvent portion of the liquid and thereafter cause bloating by fusing the earthy material and cause a reaction resulting in the liberation of gases throughout the mass.

2. The process of promoting bloating in the production of a cellular product, which consists in adding to a quantity of earthy material a liquid containing gas forming ingredients, kneading the mass to produce a plastic block, preheating the block while in moist condition to shatter the block into fragments and evaporate the solvent portion of the liquid, and thereafter subjecting a mass of the fragments to a bloating temperature to cause fusion of the fragments into a plastic mass, and the formation of cells throughout the mass by the liberation of gases evolved from the gas forming ingredients when subjected to the bloating temperature.

3. The process of promoting bloating in the formation of a cellular product, which consists in adding to a mass of earthy material a liquid containing a soluble compound including carbon, and a soluble compound including oxygen, .and in thoroughly incorpoz'ating said liquid throughout the mass of mg ingredients therethrough and m evaporating the solvent portions of the liquid and subjecting the mass to a bloating temperature adequate to cause fusion 'of the earthy material mto a lastic mass, and the forma tion of cells within the fused and plastic mass by the liberation of gas evolved 1n situ by the union of carbon and oxygen.

earthy material to" disseminate the gas form- -10 4. The process of promoting bloatinglin of June, 1930.

the formation of a cellular product, w 'ch consists in adding to a mas of earthy material a liquid eonta' a soluble compound including a carbon an a soluble compound 15 including 0 gen, and in thoro hly incorporating sai iquid throughout t e mass ofearthy material, preheating the block of earthy material while in a moistened condition to cause shattering of the same into fraga ments and the ejva oration of the solvent rtions of the liquld, and in thereafter subecting a mass of the preheated fragments to a bloating temperature to cause fusion of the fragments into a plastic mass, and to cause :5 formation of cells throughout the mass by the liberation of gases evolved by the union of carbon and oxygen.

In witness that I claim the foregoing I have hereunto subscribed my name this 28th day SHERMAN Q. LEE. 

